The present invention relates to the feed through of electrodes, through the cover of a electric arc or reduction furnace, and more particularly the invention relates to a device for running an electrode through a twin wall, water cooled hollow cylinder made of electrically conductive material which circumscribes the electrode as well as current conductors and contact brackets which may be arranged axis-parallelly around the electrode in the case of deep or dropped sockets.
German Pat. No. 2,125,773 describes structure for running electrodes through the cover of an arc furnace or of a reduction furnace under utilization of water cooled cooling jacket arranged respectively around each electrode in axis-parallel relationship. Each of these cooling jackets is provided with a fitting of an annular configuration to receive extension sleeves for pressing the contact brackets against the electrodes. Such an arrangement is disposed underneath the cover. Parts for conducting electric current to the electrodes are arranged in the immediate vicinity of the furnace and usually they are encapsulated in a cooling jacket in order to be protected against the heat of the furnace as well as against any chemically agressive gases. It was found, however, that this encapsulation does not avoid all detrimental effects which may interfere with the operation of the furnace. For example the electric current induced in the hollow cylinder forms a magnetic field which is effective in its vicinity in one way or another. The electric current of and in the hollow cylinder induces in turn an electric current in the furnace cover. This in turn entails undue inductive heating of the cover. Another disadvantage is the lossless resistance of an inductive nature, which is increased in such a manner, and entails a higher power rating, particularly for the furnace transformer as well as for the high current conductor running current to the furnace.